06 Jan Will Degreasing Eliminate Pinholes?

I am often asked about the true purpose of degreasing and if it will really eliminate pinholes. It seems that there are a number of individuals who, perhaps, on a budget-minded philosophy have eliminated degreasing entirely from their screenmaking process. Their thinking is that the ink and emulsion removing process has completely eliminated the need for degreasing.

Let’s begin with the fact that degreasing, alone, is not an anti-pinhole step, per se.

However, degreasing should be performed on all new mesh, since the manufacturer did not clean the mesh of any contaminants that might be on the mesh. Also, keep in mind that mesh can be contaminated during handling at the distribution point, in shipping, and at any point prior to coating the mesh with emulsion. And, degreasing is an important step to be performed just before the mesh is coated with emulsion. After degreasing, care should be taken that the mesh is not further contaminated by the use of fans, which might blow dust particles on the mesh. It is suggested that the screens be dried in a dust-free cabinet and once dry, be coated immediately.

In other words, degreasing is a necessary step to remove any oils or contaminants from the mesh threads that will cause the emulsion to not grab hold of the thread, or create issues will create extra work after developing. It is a benefit of the degreasing step that it can help to remove some other contaminants that are on the mesh that might cause pinholes.

However, pinholes (and fisheyes) are created by a number of things, including any contaminants left on the mesh prior to coating. Below is a shortlist of things that cause pinholes.

Unclean screenmaking department creates the possibility of dust on the wet mesh and emulsion

Any airborne contaminants can settle onto the mesh or emulsion

Contaminates in the water system that are not filtered out can create pinholes

Hard water will leave behind calcium that causes pinholes

Chemical contaminants left on the mesh can be problematic

Degreaser not thoroughly rinsed from mesh

Oils from second-hand smoking

Screens not coated as soon as they are completely dry are always subject to pinholes

Fans in the screenmaking area that blow dust on the wet mesh or emulsion

Contaminates in the emulsion

Improperly prepared emulsion

Improper scoop coater design

Coating speed is too fast

Emulsion moisture in excess of 4-6% during exposure

Contaminates on the exposure unit glass

And, yes, even too little exposure time

INDUSTRY SEGMENTS

For more than 70 years, I’ve worked and consulted in a variety of segments of the screenprinting technologies, including:

I have spent most of my life learning every aspect of the screenprinting technologies; as a business owner many times over and as a practitioner in a variety of segments in the screenprinting field. Today I mentor and coach high-achieving business owners and their staff, who are determined to create phenomenal success, in efficiency and productivity.

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A short list of the most common types of work, for which I am called upon…